Missing Phone from MTN Store Highveld Mall (Witbank) - Samsung S8

Hi, I am highly upset with the service from MTN Highveld Mall (Witbank). I gave in my cellphone for repairs on the 12th Nov and to date the repairs centre has not received my phone. When I call the store I am told that the phone was sent. I am the one that has to make follow up calls to find out where my phone is and the person I spoke to Wayne from the MTN store on 2 occasions said they will do investigations and get back to me but that never happened. I contacted customer service and they are also going to do investigations. I am without a phone for almost 4 weeks and that is the amount of time I told it will take to repair my phone however if the phone was not received how much longer would I have to wait. This is highly unacceptable as I have been a loyal customer of MTN for over 15 years. This is the first time I ever had to send my phone in for repairs and the treatment I am receiving is pathetic. I want answers as to where my phone is, how does a Samsung S8 just go missing and no-one knows where it is?